Process for coking carbonaceous material



Feb. 2, 1943. c. H. HUGHES PROCESS FOR COKING CARBONACEOUS MATERIAL 6 Sheets-Sheet 1 Original Filed Oct. 25. 1959 ATTORN EY Feb. 2, 1943.

c. YH. HUGHES y 2,309,958

PROCESS FOR COKING CARBONACEOUS MATERIAL originalLFiled oct. '25. .1959 6 sheets-sheet 2 ATTORNEY Feb. 2, 1943. c. H. HUGHES PRocEss Fon coKING cARBoNAoEoUs MATERIAL A original Fild oct. 25, 19:59 e sheets-sheet s Fe'. 2, 1943. H. HUGHES 2,309,958

FROCESS FOR COKING GARBONACEOUS MATERIAL Original Filed Oct. 25, 1939 6 Sheets-Sheet-4 'ATTORNEY Feb.. 2, 1943. C. H, HUGHES 2,309,958

PROCESS FOR COKING CARBONACEOUS MATERIAL Uriginal Filed Oct. 25, 1939 6 Sheets-Sheet 5 MN/2% BY G ATTORNEY Feb. 2, 1943. H HUGHESV 2,309,958 PRocEss FOR cokI'NG cARBoNAcEoUs MATERIAL original Filed 001'.. 25, 1939 6 Sheets-Sheet 6 ATTORNEY Patented Feb. 2, 1.943

2,309,953 y raocnss Fon, como vcmusoimicrons MATERIAL Charles E. Hughes, Glen Ridge, N. J., assignor to Hughes By-Produot Coke Oven Corporation, New York, N. Y., a corporation of New York original application october 25, 1939, serial No. 301,172. Divided vand this application March 1,

' 1941, Serial No. 381,357

- claims. (ci. 2oz-1g) The present invention relates to a process for eoking carbonaceous material and, more particularly, to a process for coking coal.

As those skilledin the art know, in the earliest times coke was produced -in mound-shaped Meilers rsimilar to the old method of burning charcoal in heaps. The beehive oven was a modifica-- tion of these except that it was built of brick instead of sod or clay, and the earliestrecord of coking coal in a regular oven is an English .10

patent to St. John granted in 1620 for making coke in a beehive form of oven. Although a l German chemist, Becher, received a patentin ,1700 for recovering tar from coking coal,'it appears `that it was not until Claytons discovery 15,

in 1737 that the formation of a combustible gas when coking coal was noticed. About the year 1767, a form of coke ,oven, producing coke and recovering some tar and ammonia, was conrecuperating ilues. This oven had the oven flues placed horizontally, the gas and air being first burned in sole flueslocated underneath the oven chamber, Jthen passing up through a riser to the ovens and down through three horizontal ilues in series. In the years 1881 to 1883, Seibel pat-- `ented an oven having horizontal ues and having neither grates nor regenerators. It is apparent that oven designs up to this time were so uneconomical of gas used in heating the ovens, or the coals were so lean in gasthat grates for burning coal were built into the ovens'x and the gas was first admitted over these grates, the

amount of coal being such as to supply ythe re- `quired additional heat.

The first ovens of the Otto type had been erected in Germany in 1881, and in the same year Huessner appropriated the Knab-Carves structed in Germany and was described as a dome-like fire clay retort. In 1781, an attempt appears to have been made to recover the byproducts, and a patent to the Earl of Dundonald was issued, and in 1792 Murdoch experimentedwith making gas from coal in retorts. efforts bore fruit, and .twenty years later the, streets of London were lighted .by gas Theearliest records: of tha' rectangular, orV retort, ovens show them in operation in Germany about 1830. They had. open walls, pierced by horizontal and vertical nues, and the walls formed a rectangular space which contained the charge.I In 1856, Knab is reported to have built a group of retort coke ovens to recover by-products and illuminating gas. ilues on the bottom only, but, of course, no regenerator or recuperator system was provided. Moreover, there was no attempt to furnish uniform heating to the oven sole, the fire or iiame These model and built a hundred ovens in Germany, thus establishing the industry on a sound basis in that country, although the quality of coke from these ovens was inferior. In these ovens the flues were horizontal. A very substantial improvement was made by Hoffman, who added the Siemens regenerator to the Otto coke oven and thus provided the first really eflicient coke oven, generally referred to in the art as the Otto- Hoffman coke oven. In 1888 Festner, a German A inventor,l changed the Otto-I-Iciman design by o using horizontal instead-of vertical iiues and These ovens had passing from a grate through ac entral flue and 40 then returning' through iiues on both sides thereof. The following year, Appolt built his ilrst ovens in the shape of vertical and, later, horizontal retorts, using his gas only for heating his oven through horizontal flues. This was about the earliest closed retort coke oven, utilizing the gas for its own heating. By, 1861 the Coppe@ coke oven of Belgian inventionwas in use on the Continent, and in 1873-74 it was introduced into and was of the non-recovery type.

About 1862 Carves of France introduced side nues in addition to the bottom iiues of Knab. About 1880, Simon, an English inventor, im-

abandoning the Siemens regenerators, replacing the same with a Ponsard gas furnace. Hoffman cooperated with Festner, and this' design was called a Festner-Hoffman oven, having horizontal flues and recuperators. In 1887, the Semet- Solvay oven came into notice, the rst of them having no recuperators or regenerators. I t appears that some of the principal features of Semets design' were the introduction of the division wall, the building of the oven Aiiue system as a sleeve out of D-shaped tile, and the starting of the combustion at the top, or No. 1, ue, and,

'in general, providing a structure which was 5 strong, easily heated and had ai'reservoir ofheat ngland. It had vertical flues v proved the Carves oven very materially by adding' 55 in the division walls.

j From the foregoing historical survey of the development of the coke oven art, it appears that all designs of ovens for coking coal sprang from four roots classified as follows:

1. The beehive oven, which was developed from the mound of charcoal burners.

2. The Coppee oven, with vertical ues in the oven walls, these ovens being built narrow, long and high..

3. TheKnab broad oven, with ues underneath.

4. The Knab oven modied by Carves, with the oven flues horizontally in the side walls as well as underneath.

The high, narrow coke ovens of the prior art described in the foregoing had various important disadvantages. For instance, a recent standard type was usually of the order of about 45 feet in length, about 16 feet high, and about 17 inches in width, and, because of their height and narrowness, they had to be constructed and built in very large individual units, so that the original cost of installation was extremely high. Generally speaking, it was not possible either to build or to operate relatively small units of the conventional type at a W cost.

Besides these economic disadvantages, the use of a high, narrow oven was limited to certain coals or coal mixtures. Coals which expanded upon coking could only be used if mixed with shrinking coals, as otherwise the wear on the walls was too great, and the increasing pressure might have led to destruction of the ovens. Using a large percentage of shrinking coals, as necessarily became general practice, the coal shrank away from the heating walls, causing the formation between coke and wall of irregular gaps and crevices`which acted as channels for the gases distilled from the coal. Due to the irregularity of these channels, heat could not be applied so as to produce a uniformly carbonized coke in a short coking period, regardless of the method of heating or.control employed.

It is well known in the art that this channel' ing brought the rich gases into immediate conproducing two unfortunate results. First, the contact of the crude gases with some 1440 square feet of brick at the highest temperature in the oven caused the destruction of a part of the valuable by-products contained in the gases. Secondly, the gases acted as an insulator between the hot walls and the coking coal, preventing considerable heat from reaching the charge by conduction. Again, the gases. being much lower in temperature than the walls, took up considerable heat from them and thus prevented this amount of heat from reaching the core of the charge at all. Both of these effects resulted in greatly retarding the coking time and were diametrically opposed to the results desired, for it 'was, of course, the purpose of the operation to transfer heat from walls to coal charge as efliciently as possible and in the shortest time. Moreover, the heating of the gases had the undesirable eiTect of passing the gases to the byproduct plant in a superheated state, necessitating larger condensing surfaces to cool them.

A further disadvantage. ofthe high, narrow coke oven was that the Width of the charge varied over the length of the oven, for practical reasons-being smaller at the pusher end than at the coke discharge end. Inorder to provide for poses and not for domestic use. Subsequently,

a .broad rectangular sole-red coke oven atl vided a rectangular sole-fired coke oven having a multiplicity of long, independent, parallel heating llues arranged side by side, each of said ues being directly connected at each end to two shallow, horizontal hair-pin regenerators below and parallel to and individual to each separate heating flue for alternately supplying heated air to the flues and receiving the heat of waste gases discharged therefrom. Each heating flue was provided with a burner'or means for supplying rich fuel gas to both ends thereof. In this manner all of the flames burned in independent and isolated flues in the same direction and extended from one end toward the other end of the oven. Thus, each heating flue and its associated regenerators could be alternately operated, independently of adjoining heating flues and regenerators.

Although this type of broad oven could be built in relatively small units, the entire heating system and the so-called regenerators were fundamentally incorrect. The oven was designed for underring with rich coke oven gas only. The use of coke oven gas with preheated /air gave a short and hot flame resulting in nonuniform heating of the long, straight, parallel and independent heating fiues. An excessively high temperature occurred at each burner, producing danger points or hot spots. Moreover,

the regenerators were so designed that the waste gas and incoming air always circulated in a horizontal direction which failed to give satisfactory and efficient results.

In other words, by eliminating some of the disadvantages of prior ovens, the broad oven described introduced new difculties which were in part much more serious than thel former. Thus, the ends of the heating flues in said broad oven were overheated` causing overcoking and quick overheating of the construction material of the oven, While black spots, too cold for proper coking, developed in the centers of the ues. Clearly, it was practically impossible to obtain proper coking of the center mass except, and then to only a small extent, by overcoking the masses at the ends of the'flues. Then, the space provided above and below the regenerators was inadequate for the gases to spread or mushroom out before going through the checkerb'rick. Moreover, the regenerators, which were individual for each flue, were insufficient in size and could not function satisfactorily. The velocity of the gases in the heating ilues was too slow and in the regenerator too high for proper heat transfer. Of course, not only did this nonuniform distribution of heat greatly decrease the over-all efficiency of these ovens, but, especially, the hot spots, developed in the operation of the' oven, caused early deterioration of the building material and greatly increased the cost of operation and maintenance. Although these diflculties were well known in the art, and, from time to time, various suggestions vand proposals were v acteristics different from those of coke produced heretofore by prior art processes.

It is a further object of the invention to provide a coking process which is easily adaptable to the coking of any carbonaceous material, such as coal, peat, tar, lignite, pitch, culm waste and other low grade coals, fuel oil, bunker oils and other petroleum products, and the like.

It is also an object of the invention to provide a coking process for coking a broad flat layer of coal to produce a coke of far greater suitability for domestic purposes than that produced in the high, narrow walls of the prior art.

The invention also provides a 'process for coking coal lin a thin layer to permit the free iiow of hot evolved gases whereby an open cell structure results.

The invention also provides a coking process wherein a flow of combustible gases at a temperature sufllcient to coke carbonaceous material is directed in a single serpentine stream beneath said material and out of contact therewith, whereby hot spots and partly under-coking and partly overcoking the carbonaceous material are avoided and whereby substantially uniform coking of said material can be obtained.-

Other and further objects and advantages of the invention will become apparent from the following description taken in conjunction with theA accompanying drawings, in which:

Fig. 1 illustrates a top plan and a horizontal plan sectional view of four ovens embodying the principles of the present-invention, taken on line I-l of Figs. 2 and 3;

Fig. 2 depicts a transverse vertical sectional view taken on line 2-2 of Fig. l;

Fig. 3 shows a front elevational view of the ovens, taken on line 3-3 of Fig. l;

Fig. 4 is a vertical longitudinal sectional view through the oven-l and regenerators taken on line Fig. 5 illustrates a front elevational view taken on line 5-5 of Fig-l, depicting the arrangement of the closed valve boxes on the coke side ofthe oven battery;

tion of air, fuel gas and waste gas in a single reversal through the series heating flues, regenerators, valve boxes and chimney flues of an air. A ilow of combustion gases at a temperature sufficient to coke the carbonaceous material-is directed in a serpentine stream beneath the sole of lsaid chamber, and said flow is alternately reversed to provide substantially uniform coking of said carbonaceous material. The process can be satisfactorily carried out in a rectangular broad coke oven heated with an uneven number of sole ilues, preferably iive, interconnected in series and arranged to support and to heat the floor of the oven. Each oven can be operated independently of the adjoining ovens. These heating ilues are connected by openings located at opposite ends with two sets of vertical regenerators located below and parallel to the heating fiues and coke ovens. The two sets of vertical regenerators are alternately used to supply preheated air to opposite ends of the series flue heating system and to receive the hot waste productsof combustion. These regenerators have spacious, chamber-like passages both above and below the checker-brick, giving the gases an opportunity to spread cr mushroom out before passing through and thus increasing the time of contact and affording more effective heat transfer. A combination air and waste gas box. equipped with the necessary valves, is provided on both the pusher and coke sides of each oven for the accurate control of the air entering the regenerator and in order vto control the draft for each oven.

A coke ,oven suitable for carrying out the process of the invention will now be more fully described to those skilled in the art, reference being had to the accompanying drawings illustrating a preferred embodiment thereof. Similar reference characters denote correspondingparts throughout the various figures.

Referring, now, more specifically t0 Figs. 1 to 4, reference characters -I, 2, 3, 4 and 5 denote the heating fiues arranged in horizontal position, running parallel to the length of the oven, and connected in series under the iloor of the oven. The interconnected heating flues are provided with burning means, such as gas burners B-I B-2, B--3 and B-4 which are supplied with fuel gas under a moderate and constant pressure through supply manifolds F-I and F-Z (Fig. 4). pipes G-l and G-2 (Fig. 4) to burners B-I, B-2, B-3 and B'4 (Fig. 1), and the fuel gas is regulated through a special T and an orifice (Fig. 12) Below each oven are located two sets of regenerators Rf-I, R-2 and R-3, Rf-d, built oven in accordance with the process of this in.

vention; and

Fig. 12 is a vertical section through the special T and diaphragm assembly through which the volume of fuel gas to each burner is regulated.

Broadly stated, the present invention relates to ai" process for coking a broad flat layer of carbonaceous material in a coking chamber wherein it can be sealed against the admission of of standard checker brick or special checker brick in the usual manner. Regenerators R-I and R-Z are connected with series flue 5 and chimney iiue C-I by passages P-l to P-I-8 inclusive. Regenerators R-3 and R-4 are connected with series flue I and chimney flue C-r-2 by passages P-S to P-I6, inclusive. The alternate flow of waste gas and air and the crculationthrough the heating fiues, regenerators and waste gas flues are controlled by the reversing dampers in the valve boxes, as will be more fully explained hereinafter. (See Fig. 11.)

The valve boxes may be of any suitable design and appropriate construction, as those skilled in the art will readily understand. It is preferred, however, to use valve boxes ofthe type illustrated in Figs. 7 to. 10. It is to be observed that the preferred form of valve box has a single housing A, preferably a suitable metal casting, as of a corrosion-resistant material, such as alloy cast iron of the chrome type or the chrome-nickel The fuel gas is conducted through.

type or the like. In the housing is mounted at the top thereof an air inlet damper or valve V-2 of rectangular shape, the face of which, V--2I,` is adapted to make a substantially airtight Contact with the seat V-22 of a rectangular port V-23 in the top of the box or housing. Slightly projecting shelves V-24 on each of two opposite sides of the opening V-23 just below seat V-22 provide a seat upon which removable air-regulating bars B can be placed. The valve V-2 is supported by a valve stem V-25 which is keyed to a rotatable shaft S-l. The shaft is held in position by a suitable sleeve mounting S-4 which is rigidly fastened to the housing.

Inside the housing of the valve box, a valve chest is formed, and within this valve chest is mounted a waste gas exit damper or valve D-2, the face D-2I of which -is adapted to make a Asubstantially air-tight contact with the seat D22 of a port D-23 at the bottom of the box. This port forms theupper end of passage or duct'P-IE which connects the valve chamber with chimney flue C--2. The valve D-2 is supported by valve stem D-25, which is keyed to a rotatable shaft S--2. This shaft is mounted in a suitable sleeve mounting SV-S, which is rigidly fastenedl to valve box A, and the shaft extends through the side of and outs-ide the box.

Keyed to one end of rotatable shaft S-I is the fulcrum of a bell crank V-8. The bell crank has a straight arm which is connected by a suitable connection to a cable C which runs around the entire battery of ovens. 'Ihe other arm of I the bell crank is curved outward and over the edge-of box A and at its end it connects with a vertical adjustable rod S-3. This rod comprises three parts: the upper part S-3I connecting at the upper end thereof with the bell crank and with its lower end threaded; a turnbuckle S-32 which is screwed onto the threaded end of S-3I, and a lower part S-33 having either a swivel or a thread at its upper end adapted to coact with S-32 and connected at its lower end to a lever V-4. Lever V--4 is keyed to the end of shaft S.-2 which protrudes from the side of the valve box. The turnbuckle is adjusted to make rod S-3 of such length that air valve V-2 is open when waste gas damper D-2 is tightly closed, and vice versa.

In passage P--I6 there is a rectangular plate damper D-B adapted to close off the passage in any degree required. It is mounted on a shaft S-G which forms its longitudinal axis.

' This shaft extends the width of the passage, and

one end of it passes-through a side of the passage. The shaft is suitably mounted in the sides of passage P-I6. To the end of shaft S-B which'protrudes from the side, a quadrant Q is attached.

The reversing mechanism for operating the air and waste gas dampers isv not shown, as those skilled in the art are familiar with the construction and operation. It may be briefly described as consisting of a motor' driven drum around which the endless cable C is wound. A time clock, which is set for fixed reversal periods, is adapted to make thenecessary electrical contacts required for starting and stopping the motor and for shifting the gears which change the direction of travel of cable C. The cable is of the oven battery, and cablelC, which extends around the entire oven battery, is wound around the motor drum and is adapted to travel in opposite directions at each side of the battery. Thus, all air inlet valves or dampers on the pusher side of the battery are open, and all waste gas dampers are closed; during the same reversal period, the air valves on the discharge side are closed, and the waste gas dampers are open, thus completing the circulation through the heating system and regenerators. 'Ihe opposite is true during the alternate reversal period.

The operation of this improved broad coke oven will now be described, particularlyin conjunction with Fig. ,11, which illustrates diagrammatically the flow of gases through the several flues, ducts, regenerators, dampers and valves, for the convenience of those skilled in the art.

Assuming that the regenerators R-l and R-2 are being preheated by the outgoing gases of combustion, valve V-I is closed and damper D-I in passage P-B is opened, permitting a flow of waste gas to chimney ue C-I. The air to be preheated enters through valve V-2, damper D-Z in passage P-IB being closed. The air flows into passage P-I 5, which is large enough to permit it to mushroom out, and then uniformly up through the hot checkerbrick in regenerator R-4 to passage P-I4, whence by passages P-I3 and P-I2 'adapted for alternately opening and lclosing all the now partially heated air is brought to the spacious passage P-H below regenerator R-3. The air then passes up through the checkerbrick in regenerator R-3. This checkerbrick is hotter than that in regenerator R-4, and the already heated air, on passing through, is brought to a very high temperature. It will be observed that provision of relatively large gas spaces above and below the regenerators permits the gas (here, air) I to spread out before entering the checkerbrick and thus slows down its passage through the regenerators, giving improved heat transfer. The hot air passes along passage P--IU above regenerator R-3 and up passage P--9 to heating flue l. This preheated air for the combustion of the fuel gas at the burners is delivered in ue I in great excess over the air requirements for burner B-I and, after the combustion at burner B-I, the air, still in considerable excess of the requirements of the next burner in the series, passes mixed with the products of combustion to burnerV B-2, and similarly to all burners successively.

The hot waste gases of combustion pass out of the series iiue heating system from flue 5 through passage P-I to passage P-2, which is sufficiently large for the gases to spread uniformly, and then downward, relatively slowly, through regenerator R-L 'I'he waste gases arevery hot at this point and give up a great deal of their heat to the checkerbrick in regenerator R-I, becoming considerably cooler as they pass down into passage P-3 below the regenerator. The gases are then brought through passages P--4 and P'5 to the roomy passage P-6 above regenerator R-2, and thence go down at reduced velocity through the of their remaining heat thereto and to emerge considerably cooler in passage P -1 below. These cooled combustion products flow through passage,.-

P-8 and damper D-LI into chimney flue C-I.

It is evident from the foregoing that,fdur ing the operation in the direction detailed in the paragraphs immediately preceding the present one,l

(i. e., air entering at valve V.-2 and waste gases going 4to the stack through damper D-I and chimney ue Cv-I the draft set up is in the di,- rection from heating flue I, through ues 2, 3 and 4, to heating flue 5. Therefore the flame at ,burner B-I, located at the turn between flues I and 2 (see also Fig. l), is deflected by the draft into flue 2. Similarly, the iiames of burners B-2, B-3 and B4 are deflected into ilues 3, 4 and 5, respectively. Thus, with the draft in this direction, there is no flame in flue I, and the flames are burning at the coke end (with respect to the oven) of iiues 2 and 4 and at the pusher end of flues 3 and 5. The hottest end of iiue 2--and this ap- 10 plies as well to flue 4,-is under the coke end of the oven, and the ue gets progressively less heat from burner B-I as one moves downtoward the pusher end. Contrariwise, the hottest ends of flues 3 and 5 are those under the pusher end of the oven, while '15 they get least heat from burners B-2 and B--4, respectively, at the ends under the coke end of the oven. It is obvious from this that fiuesl 2 and 4 furnish most heat to the coke end of the ovenjon this run, somewhat less to the centre, and least to the pusher end, while flues 3 and 5 furnish most heat to the pusher end of the oven, somewhat less to the centre, and least to the coke end. Adding these two effects, the conclusion is arrived .at that the sum of the heat furnished at any point along the length of the oven is about the same as at any other point, irrespective of the distance from the actual burners themselves.

Upon a reversal of the draft, accomplished as described supra, with the preheated air entering so at the coke end (with respect to the oven above) of flue 5, the ames of burners B-B, B-3, B-2 and B-I are deflected into fiues 4, 3, 2 and I, respectively. In this case, then, the flames burn at the pusher ends of ilues 2 and 4 and at the coke ends of flues I and 3, so that the effect of each individual ue upon the oven is just opposite to that detailed in the foregoing paragraph. The cumuiative or additive effect of the whole series of flues.

beneath the oven, however, is exactly the same as w in the other case. In other words, the heat furnished throughout a full cycle is practically uniform for the entire oven length, so that, with no black spots possible at the centres of the flues, there can be neither overcoking at the ends of the oven nor undercoking at its centre. Moreover, the reversal of the flames, being deflected alternately from one ue into another, eliminates the dangerof hot spots. f

When the regenerators R--I and R-2 are raised to the temperature necessary for preheating the air, the directions of :dow of the air and the waste gases are reversed bypening damper D-2 and valve V-I and closing damper D-I and valve V-2. Air then enters through valve V-I and, damper D-I in passage P-Il being closed. flows through passage P-- and upward through regenerators R--Z and R-I in series, by means of the interconnecting passages P-S to P-2, described supra. Passage P-I then connects with heating flue 5. As detailed immediately above, the ames are then deected by the draft into heating ues 4, 3, 2 and I. The waste gases flow downward through regenerators R-3 and .Rf-4

and through interconnecting passages P-S to 65 The operation of the valve boxes is clear from Figs. 'Ito 10. In the position shown, cable C has traveled to the left, moving the straight arm of bell crank V- 8 ln the same direction. The bell crank has turned shaft s-l te which it is keyed. 7

This movement of the shaft has raised air valve V-2 from its seat. The curved arm of bell A crank V-8 has been moved downward in lan are and has pushed down upon adjustable rod 8 3, which has in turn depressed lever V-4. Lever V-4 has turned shaft S-2, to which it is keyed, and this in turn has lowered damper D-2 into its seat. The travel to the right of the cable reverses this order, opening damper D-2 and closing air valve V2.

'I'he open position of the air valves V-2 on the pusher side of the battery is illustrated by Fig. 6, which shows the cable as having traveled to the left. The arrangement of the damper boxes on the coke side at the same time is depicted in Fig. 5, air valves VI being closed.

Stack draft is used for drawing air into the regenerators and for removing the gases of combustion. The stack draft for each separate coke oven is regulated by the position of the plate damper D--6, which is held in position in the passage to the chimney flue by quadrants Q. The air valves are equipped with air-regulating bars B, as mentioned supra. Bars B are movable, and the volume of air to each regenerator is controlled by the size and number of removable bars used to regulate the size of the opening into the body of the box (see Fig. 10) Y In the operation of the oven as an entire unit, oven doors W-I and W-2 are closed and sealed air-tight, as may be seen from Fig.`4. Coal is charged through the charging holes H in the top of the oven (see also Figs. 1 and 2), and the cone-shaped piles are levelled off in the usual manner by levelling ram K, introduced through a small door in the pusher side oven door W-2 (see Figs. 4 and 6). The charging hole covers N are replaced and sealed air-tight. Fuel gas is stantially uniform coking temperature for the entire area of the oven sole upon which the coal charge is supported. As is well known by those skilled in the art, the coking -temperature varies depending upon whether low or high carbonization is desired. Thus, a. suitable temperature for low coking, such as about 600 to about '100 C., to a suitable temperature for high coking, for instance, about 1150 to about 1450 C., can be successfully used. Reversal periods' of suitable duration are employed, as those skilled in the art will know. and a reversal about every 15 minutes has been found to give satisfactory results. An off-take pipe M at the end of the oven provides an outlet for the gases evolved during coking,

and these pass to the by-product plant. After the coal is coked, oven doors W--I and W-2 are removed, andthe coke is pushed in the customary way.

In providing gas for heating the ovens, the fuel gas, under a. slight and constant pressure. is conducted through supply manifolds F--I and F-2 and into risers G-I and G-2 (see also Fig. 3). Its supply to the burners is regulated through a special T, conveniently located in each of the risers 'G--I and G-2. This T, shown in Fig. 12, is so designed that, by removing plug T,I, the diaphragm T--2 can be replaced with one having a larger or smaller orice, as required. V

As noted supra in the structural description of the valve boxes, the air supply for each separate oven is regulated .by the size vand number .of removable lbars B. (see Figs. 9 and 10) which are placed inthe openings of the air valves at the two ends of the oven. air control at each oven and, together with the fuel' gas control provided byA means of the special T. permits independent and accurate con- This gives accurate trol of the performance of each individual oven. This, with the other advantageous'features described herein, gives my novel and improved process combination a iiexibility of operation never before attained by the coke oven art.

It will also be appreciated that, according to my novel process, it is possible to produce a coke which is far more suitable for domestic purposes than was the coke produced by the processes employed in the high, narrow ovens of the prior art. The pressure in the plastic mass resulting from a deep, narrow charge materially affected the coke structure, so that a hard, dense, slowburning coke having a close cell structure was n'ecessarily produced. Such coke was really only suitable for metallurgical purposes, although the surplus was sold for domestic uses. Coke for domestic use should have an open, free-burning cell structure, and this type of coke can be made by my process. Leveling o" the coal charge in an oven using my process over the entire horizontal heating surface gives a thin layer of about to about 18 inches in depth spread evenly over i a surface about 35 to about 45 feet long and about 8 to about 12 feet wide. The free flow of hot, evolved gases through the thin coal charge and the low pressure towhich the coal in the plastic state is subjected create entirely-different carbonizing conditions from those prevailing in the high, narrow ovens. An open cell structure results, and, in addition to the fact that a diiferent molecular arrangement of the coke structure is developed, the carbonizing reaction is accompanied by less than the amount of cracking of by-products which resulted from contact with the hot, vertical surfaces of the prior art. Thus,

the broad, iiat oven herein described in connectionvwith' my improved process can be operated to leave a suitableQvolume of volatile matter in the coke to insure the free-burning properties desirablein domestic coke. It will, of course, be understood that an appropriate mixture of coals can as readily produce a high grade metallurgical cpke by my novel process, so that my process has the greatadvantage of being adaptable to the production of either domestic or metallurgical coke.

Although the present invention has been disclosed in connection with a preferred oven construction for carrying out the same, variations and modifications of this construction may be resorted to by those skilled in the art, without departing from the principles of the invention. Thus, While a preferred arrangement of valves has been described and a preferred reversing mechanism for their operation has been indicated, those skilled in the coke oven art will readily perceive that other operative valvular means could be substituted for my arrangement and that other valve-actuating means could be used with satisfactory results. It will also be observed that, While I have preferred to employ a regenerative system under each oven which comprises two sets of vertical regenerators with each set comprising two regenerators connected in series, sets of one regenerator or of three or more seriesconnected regenerators could be satisfactorily used with relatively minor alterations and adjustments. Moreover, while I have described my 'invention particularly with reference to the coking of coal, it will be readily understood that it l' is as easily adaptable to the coking of any carbonaceous material, such as peat, tar, lignite,

Y pitch, culm waste and other low grade coals, fuel oil, bunker oils and other petroleum products,

introducing carbonaceous material into said coking chamber; spreading said carbonaceous material onto the sole of said coking chamber in a layer that is thinner than its Width vand length; sealing said oven against the admission of air; establishing under substantially the entire sole of said coking chamber and substantially parallel and immediately adjacent thereto a flow of hot combustion gases to furnish heat at a temperature sufficient to coke said carbonaceous material on the sole of said coking chamber; changing the direction of said ilow of hot combustion gases at predetermined space intervals under the sole of said coking chamber to provide a, single and continuous serpentine stream of hot combustion gases under substantially the total area of the sole of saidcoking chamber and in a plane substantially parallel to the sole of said coking chamber; alternately reversing the direction of said flow of hot combustion gases at predetermined time intervals to reverse the entire single and continuous serpentine stream of hot combustion gases, whereby uniform heating conditions over substantially the total area of the sole of said coking chamber can be attained and whereby hot spots and partly -overcoking and partly undercoking the carbonaceous material on the'sole of said coking chamber are avoided; and continuing said alternate reversals until the entire volume of the layer of carbonaceous material in said coking chamber is fully coked, whereby carbonaceous material is coked in said coking chamber substantially uniformly.

2. The process of coking carbonaceous material in a coking chamber of a long rectangular oven broader than its height, which compises introducing carbonaceous material into said coking chamber;v spreading said carbonaceous material onto the sole of said coking chamber in a layer stantially parallel individual streams to provide substantially parallel individual streams wherein preheated air flows in opposite directions in adjacent streams; alternately merging the ends of adjacent individual streamsl to combine the ow of preheated combustion air in said plurality of substantially parallel individual streams of preheated combustion air into a single and continuous serpentine stream of preheated combustion air under substantially the total area of the sole of said coking chamber; introducing a uid fuel at the merged ends of adjacent individual streams ofr preheated combustion air in said single and continuous serpentine stream of preheated eombustion air, whereby the Adirection of flow of preheated combustion air in said adjacent individual .streams will determine the individual stream in which the fluid fuel will lnow; burning said fluid fuel in said plurality of substantially parallel individual streams of preheated combustion air to propagate therewith a plurality of names alternately traveling in opposite directions in said individual streams to furnish heat to the .sole of said coking chamber at a temperature sumcient to cokethe carbonaceous material thereon; .alternately reversing the direction of flow of said preheated combustion air in said single and continuous serpentine stream of preheated combustion air to propagate the yflames in the adjacent individual streams and in directions oppo'site to those prior to reversal, whereby uniform heating conditions over substantially the total area of the sole of said coking chamber can -be attained, and whereby hot s pots and partly overcoking and partly undercoking the carbonaceous material on the sole of said coking chamber are avoided; and continuing said alternate reversals until the entire volume of the layer of carbonaceous material in. said coking chamber is fully coked, whereby carbonaceous material is coked in said coking chamber substantially uniformly.

'3. The process of coking carbonaceous material in a coking chamber of a long rectangular `oven broader than its height, which comprises sole of said coking chamber having their ends at predetermined space intervalli under the sole of said coking chamber; merg'iig', the ends of said plurality of substantially`v parallel individual streams of hot combustion gases to form a single stream and to change the direction of flow of hot combustion gases; alternately reversing the direction of said flow' of hot combustion gases at predetermined time intervals in said plurality of merged substantially parallel individual streams, whereby uniform heating conditions over substantially the total area of the sole of said coking chamber can be attained and whereby` hot spots and partly overcoking and partly undercoking the carbonaceous material on the sole of said coking chamber are avoided; and continuing said alternate reversals until the entire volume of the layerof carbonaceous material on the sole of said coking chamber is 4fully coked', wherebycarbona-- ceous material is coked substantially uniformly.

a. The process of coking carbonaceous material in a coking chamber of a long rectangular oven broader than its height, which comprises introduoing carbonaceous material into said coking chamber; spreading said carbonaceous material onto the sole of the coking chamber in a layer .that is thinner. than its width and l ngth; sealing saidoven against theadmlssion o air; establishing. a .single streamof combustion air in a nar-l l .row.,-conduit; introducing said single stream of combustion air into a spacious chamber, thereby reducing, the velocity of said single stream of combustion air; passing said single stream of combustion air in a plurality of upward currents in contact with hot refractory surfaces to effect a transfer of heat from said hot refractory surfaces to saidcombustion air to preheat the same; merging said plurality of upward currents into another single stream; confining said single stream of preheated combustion air vin another narrow conduit to increase the velocity thereof; passing said single stream of preheated combustion air under the soleof said coking chamber in a plurality of substantially parallel individual streams having their ends at predetermined space intervalsunder the sole of said coking chamber; alternately changing the directionI of flow of preheated combustion air in said plurality of substantially parallel individual. streams of preheated combustion air to provide substantially parallel individual streams wherein preheated combustion air flows in opposite directions in adjacent individual streams; alternately merging the ends of adjacent individual streams to combine the ow of preheated combustion air in said plurality of' substantially parallel individual streams into a single and continuous serpentine stream -f preheated combustion air under substantially the total area of the sole of said coking chamber; introducing a uid fuel at the merged ends of adjacent individual streams of preheated combustion air in said single and continuous serpentine stream of preheated combustion air, whereby the direction of iiow of preheated combustion air in said adjacent individual streams Will determine the individual stream in which the uid fuel will flow; burning said fluid fuel in s'aid plurality of substantially parallel individual streams of preheated combustion air to propagate therewith a plurality of flames alternately traveling in opposite directions in said plurality of individual streams to furnish heat to the sole of said coking chamber at a temperature suiicient to coke the carbonaceous material thereon; alter-v nately reversing the direction of iow of said preheated combustion air in said single and continuous serpentine stream of preheated combustion air of propagate the flames in the adjacent individual streams and in directions `opposite to those prior to reversal, whereby uniform heating conditions over substantially the total area of the sole of said coking chamber can be attained, and whereby. hot spots and partly overcoking and partly undercoking the carbonaceous material on the sole of said coking chamber are avoided: and continuing said alternate reversals until the entire volume of the layer of carbonaceous material in :said coking chamber is fully coked, whereby carbonaceous material is coked in said coking chamber substantially uniformly.

5. The process of coking carbonaceous material in a coking chamber of a long rectangular oven broader than its height, which comprises introducing carbonaceous material into said coking chamber; spreading said carbonaceous material onto Ithe sole of the coking chamber in a layer that is thinner than its width and length; sealing said oven against the admission of air; establishing a single stream of combustion air in a narrow conduit; introducing said single stream of combustion air into a spacious chamber, thereby reducing the velocity of said single stream of combustion air; passing said single stream of combustion air in a plurality of upward currents in contact with hot refractory surfaces toeiect a transfer of heat from said hot refractory surfaces to said combustion air to preheat the same; merging said plurality ofv upward currents into another single stream; confining said single stream of preheated combustion air in another narrow conduit to increase the velocity thereof; passing said single stream of preheated combustion air under the sole of said coking chamber in a plurality of substantially parallel individual streams having their ends at predetermined space intervals under the sole of said coking chamber; alternately changing the direction of iiow of preheated combustion air in said plurality-of substantially parallel individual streams of preheated combustion air to provide substantially parallel individual streams wherein preheated combustion air flows in opposite directions in adjacent individual streams; alternately merging the ends of adjacent individual streams to combine the flow of preheated combustion air in said plurality of substantially parallel individual streams into a single and continuous serpentine stream of preheated combustion air under substantially the total area of the sole of said Coking chamber; introducing a fluid fuel at the merged ends of adjacent individual streams of preheated combustion air in said single and continuous serpentineistream o'f preheated combustion air, whereby the direction of ow of preheated combustion air in said adjacent individual streams will determine the individual stream in which the fluid fuel will flow; burning said uid fuel in said plurality of substantially parallel individual streams of preheated combustion air to propagate therewith a plurality of flames alternately traveling in opposite directions in said plurality of individual streams to produce a single and continuous serpentine stream of combustion products to furnish heat .to the sole of said coking chamber at a temperature su'lcient to coke the carbonaceous material thereon; introducing said stream of hot combustion products into another spacious chamber, thereby rieducing the velocity thereof; passing said stream of hot combustion products in a plurality of downward currents in contact with refractory surfaces to effect a transfer of heat from said stream of hot combustion products to said refractory surfaces; merging said plurality of downward currents into another single stream; confining said single stream in another narrow conduit, thereby ncreasing the velocity thereof; passing said single stream to a waste gas stack; alternately reversing the direction of ow of said combustion air, said preheated combustion' air, said preheated combustion air in said single and continuous serpentine stream beneath the sole of said coking chamber to propagate the llames in the adjacent individual streams and in directions opposite to those prior to reversal, whereby uniform heating conditions over substantially the total area of the sole of said coking chamber can be attained and whereby hot spots and partly overcoking and partly undercoking the carbonaceous material on the sole of said coking chamber are avoided, and alternately reversing the direction of flow of said hot combustion gases; and continuing said alternate reversals until the entire volume of the layer of carbonaceous material on the sole of said coking chamber is fully coked,

whereby carbonaceous material is coked substantially uniformly. i

CHARLES H. HUGHES. 

